1. Field
One or more embodiments relate to a technology for interpolating images using a reference block depending on a direction.
2. Description of the Related Art
In currently commercialized digital cameras, an image sensor including a color filter array (hereinafter, referred to as “CFA”) and an I-plane optical sensor may be used. The CFA arranged in a Bayer pattern type may filter lights to enable only one signal of red (R), green (G), and blue (B) color elements to form in a single pixel.
In this manner, a process of restoring an RGB (red, green, and blue) full color image, that is, three pieces of R/G/B from the 1-plane image obtained in the Bayer pattern type may be referred to as a CFA interpolation algorithm or a CFA demosaicing algorithm. In general, a local area of images may have a high spatial correlation characteristic and a high spectral correlation characteristic, which are utilized in the CFA interpolation algorithm. However, when the high spatial correlation characteristic is not appropriately utilized in the CFA interpolation algorithm, a defect such as zipper artifact may occur. Also, when the high spectral correlation characteristic is not appropriately utilized in the CFA interpolation algorithm, a defect such as false color may occur.
For example, in a case of an image including a high frequency image signal such as an edge, defects such as the zipper artifact, the false color, and the like may be easily induced. That is, when an interpolation is performed in a direction that does not conform to an edge direction, the above described defects may frequently occur.
Accordingly, accurately estimating interpolation directivity by utilizing the above described two characteristics of the local area may be a necessary condition for a high quality CFA interpolation.